Aeration (also called aerification or aeriation) is the process by which air is circulated through, mixed with or dissolved in a

liquid A liquid is a nearly incompressible fluid that conforms to the shape of its container but retains a (nearly) constant volume independent of pressure. As such, it is one of the four fundamental states of matter (the others being solid, gas, a ...

or other substances that act as a

fluid In physics, a fluid is a liquid, gas, or other material that continuously deforms (''flows'') under an applied shear stress, or external force. They have zero shear modulus, or, in simpler terms, are substances which cannot resist any shear ...

(such as soil). Aeration processes create additional surface area in the mixture, allowing greater chemical or suspension reactions.

Aeration of liquids

Methods

Aeration of liquids (usually water) is achieved by: * passing air through the liquid by means of the Venturi tube, aeration turbines or

compressed air Compressed air is air kept under a pressure that is greater than atmospheric pressure. Compressed air is an important medium for transfer of energy in industrial processes, and is used for power tools such as air hammers, drills, wrenches, and o ...

which can be combined with diffuser(s) air stone(s), as well as fine bubble diffusers, coarse bubble diffusers or linear aeration tubing. Ceramics are suitable for this purpose, often involving dispersion of fine air or gas bubbles through the porous ceramic into a liquid. The smaller the bubbles, the more gas is exposed to the liquid increasing the gas transfer efficiency. Diffusers or

sparger In chemistry, sparging, also known as gas flushing in metallurgy, is a technique in which a gas is bubbled through a liquid in order to remove ''other'' dissolved gas(es) and/or dissolved volatile liquid(s) from that liquid. It is a method of d ...

s can also be designed into the system to cause turbulence or mixing if desired. Porous ceramic diffusers are made by fusing aluminum oxide grains using porcelain bonds to form a strong, uniformly porous and homogeneous structure. The naturally hydrophilic material is easily wetted resulting in the production of fine, uniform bubbles. On a given volume of air or liquid, the

surface area The surface area of a solid object is a measure of the total area that the surface of the object occupies. The mathematical definition of surface area in the presence of curved surfaces is considerably more involved than the definition of arc ...

changes proportionally with drop or bubble size, the very surface area where exchange can occur. Utilizing extremely small bubbles or drops increases the rate of

gas transfer Gas is one of the four fundamental states of matter (the others being solid, liquid, and plasma). A pure gas may be made up of individual atoms (e.g. a noble gas like neon), elemental molecules made from one type of atom (e.g. oxygen), or com ...

(aeration) due to the higher contact surface area. The pores which these bubbles pass through are generally micrometre-size.

Uses of aeration of liquids

* To smooth (

laminate Lamination is the technique/process of manufacturing a material in multiple layers, so that the composite material achieves improved strength, stability, sound insulation, appearance, or other properties from the use of the differing materials ...

) the flow of tap water at the faucet. * Production of aerated water or cola for drinking purposes. * Secondary treatment of

sewage Sewage (or domestic sewage, domestic wastewater, municipal wastewater) is a type of wastewater that is produced by a community of people. It is typically transported through a sewer system. Sewage consists of wastewater discharged from residenc ...

or industrial wastewater through use of aerating mixers/ diffusers. * To increase the oxygen content of water used to house animals, such as

aquarium fish Lists of aquarium life include lists of fish, amphibians, invertebrates and plants in freshwater, brackish and marine aquariums. In fishkeeping, suitable species of aquarium fish, plants and other organisms vary with the size, water chemistry and ...

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* To increase oxygen content of wort (unfermented beer) or

must Must (from the Latin ''vinum mustum'', "young wine") is freshly crushed fruit juice (usually grape juice) that contains the skins, seeds, and stems of the fruit. The solid portion of the must is called pomace and typically makes up 7–23% of t ...

(unfermented wine) to allow yeast to propagate and begin

fermentation Fermentation is a metabolic process that produces chemical changes in organic substrates through the action of enzymes. In biochemistry, it is narrowly defined as the extraction of energy from carbohydrates in the absence of oxygen. In food ...

. * To dispel other dissolved gases such as carbon dioxide or chlorine. * In chemistry, to oxidise a compound dissolved or suspended in water. * To induce mixing of a body of otherwise still water. *

Pond aeration Water aeration is the process of increasing or maintaining the oxygen saturation of water in both natural and artificial environments. Aeration techniques are commonly used in pond, lake, and reservoir management to address low oxygen levels or a ...

Aeration of liquid solids

Aeration of soil

In soil, aeration refers to the extent of air gaps. Soil aeration is the process of using mechanized or manual equipment to either puncture the soil with spikes (spike aeration) or remove approximately 1" x 2" cores of soil from the ground (core aeration). Aeration may be overlooked when trying to restore a lawn but is vital to bring it back to health. It improves drainage and reduces puddles formation. Spike aeration involves the use of an aeration machine with spikes up to a foot or more in length. It is sometimes used to address drainage issues in areas with turf. Core aeration is done on turf areas as a means of reducing turf compaction, reducing thatch buildup, improving the infiltration of water/nutrients, encouraging deeper roots, and creating an environment where grass seed can have direct contact with the soil. There are many types of lawn aerators including walk behind models, ride on versions and tractor pulled versions, as well as spiked shoes. Liquid aeration involves applying a fortified liquid solution to the lawn. The active ingredient, ammonium lauryl sulfate, is commonly found in soap. The solution breaks down dense particles in the soil and loosens it up, creating beneficial airways. Liquid aeration is a more efficient and less stressful way of loosening soil compaction. Liquid aeration, in combination with liquid fertilizers, is more effective at bringing the pH of the soil back into balance when compared to core aeration. Furthermore, the underlying science shows it significantly lowers soil compaction while conserving the health of current turf.

Aeration in food

Refers to the process in which air is absorbed into the food item. It refers to the lightness of cakes and bread, as measured by the type of pores they contain, and the color and texture of some sauces which have incorporated air bubbles. In wine tasting, a variety of methods are used to aerate wine and bring out the aromas including swirl wine in the glass, use of a decanter to increase exposure to air, or a specialized wine aerator. Cider from Asturias is poured into the glass from a height of about 1 metre (''el escanciado'') to increase aeration.

References

{{reflist, 2 Chemical processes Gas technologies